Wood screw manufacturing process



Sept. 22, 1953 s. CHIABERTA woon SCREW MANUFACTURING PROCESS Filed July 19, 1947 Patented Sept. 22, 1953 WOOD SCREW MANUFACTURING PROCESS Serafino Chiaberta, Milan, Italy, assignor to B. E. V. I. Bulloneria e Viteria Italiana, Soc. a resp.

lim., Milan, Italy Application July 19, 1947, Serial No. 762,165 In Italy April 27, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires April 27, 1966 7 Claims. 1

The present invention relates to a wood screw manufacturing process, and more particularly to a process where the threads are formed entirely by stamping operations.

It is an object of the present invention to greatly reduce manufacturing costs as compared to the costs of known manufacturing processes.

The process of the invention includes three successive stamping operations as follows:

1. In the first operation a portion of a cylindrical rod stock is compressed, where the stock is to be cut, between a first pair of dies to flatten the stock on opposite sides and change the round cross-section thereof to a substantially rectangular cross-section.

2. In the second operation, the flattened portion obtained by the first operation is pressed between a second pair of dies arranged at 90 to the first pair of dies, the second pair of dies being shaped to form rough threads. The second pair of dies compress the flattened portion of the stock along the major axis of its rectangular cross-section in order to reduce this major axis and form a substantially elliptical cross-section.

3. The third operation consists of stamping the portion of the rod treated in the first two operations with a third pair of dies arranged at 90 to the second pair of dies (that is, in the same direction as the first pair of dies of the first operation), and the third pair of dies work along the major axis of the elliptical cross-section of the rod portion to form a circular cross-section.

With these three successive operations, a thread free of burrs will be obtained.

After the stamping operations, the stock is provided with a screw head and a screw.

The process of the present invention may be performed on a machine for making rivets.

The above operations may be carried out on a continuous wire to which the first pair of dies are applied at intervals in order to produce a continuous wire having flattened portions on which the second and third of the above-described operations may be performed.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additiona1 objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic illustration of the first of the above-mentioned operations;

Fig. 2 is a diagrammatic illustration of the second of the above-mentioned operations;

Fig. 3 is a diagrammatic illustration of the third of the above-mentioned operations;

Fig. 4 is an elevational fragmentary View of the stock before it is worked on by the process of the present invention;

Fig. 5 is an elevational, fragmentary view of the stock after it is acted on by the dies of Fig. 1;

Fig. 6 is an elevational, fragmentary View of the stock after it is worked on by the dies of Fig. 2;

Fig. 7 is an elevational, fragmentary view of the stock after it is worked on by the dies of Fig. 3;

Fig. 8 is an elevational View of the finished wood screw;

Fig. 9 is a transverse sectional view of the stock of Fig. 4;

Fig. 10 is a transverse sectional view of the stock of Fig. 5;

Fig. 11 is a transverse sectional View of the stock of Fig. 6 and Fig. 12 is a top plan view of the stock of Fig, 7.

Referring now to the drawings, the stock, in the form of a length of metal wire l of circular cross-section, is first compressed between the dies 2, 2' in order to produce in the stock I the flattened portions 3. These flattened portions 3 provide the stock, at the stamped part thereof, with a substantially rectangular cross-section, as is clearly evident from Figs. 2 and 10.

The flattened portion 3 is then compressed along its main axis by the second pair of dies 4, 4, as shown in Fig. 2, to produce the elliptical section 6 shown in Figs. 3 and 11. The dies l, 4' are respectively provided with portions 5, 5 for forming rough threads while at the same time producing the elliptical section t.

Then the elliptical portion 6 is compressed along its major axis between the pair of dies 7, I to again provide a circular cross-section 9 in the stock, and the dies 2, l are respectively provided with portions 8, 8' for forming the final threads of the wood screw, and these threads will be free of burrs.

The stock is then worked on in a known way to produce the finished wood screw it.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of wood screw manufacturing process differing from the types described above.

While the invention has been illustrated and described as embodied in forming wood screws by die p ng operations, it i not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present'invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can b applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A method of manufacturing wood screws, comprising in combination, the steps of pressing a metal piece of circular cross-section into a piece having substantially a rectangular cross section, pressing a thread into the small sides of the rectangular cross section and transforming thereby the piece into a piece having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, and pressing a thread into the small sides of the ellipitical cross-section, thereby reducing the cross-section of the metal piece into a circular cross-section.

2. A method of manufacturing wood screws comprising the steps of pressing a metal piece of circular cross-section into a piece having substantially a rectangular cross-section, pressing a thread into the small sides of the rectangular cross-section and transforming thereby the piece 1 into a piece having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, pressing a thread into the small sides of the elliptical cross-section, thereby reducing the cross-section of the metal piece into a circular cross-section, and shaping the screw head.

3. A method of manufacturing wood screws, comprising the steps of pressing a metal piece of circular cross-section into a piece having substantially a rectangular cross-section, pressing a thread into the small sides of the rectangular cross-section and transforming thereby the piece into a piece having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, pressing a thread into the small sides of the elliptical cross-section, thereby reducing the cross-section of the metal piece into a circular cross section, and shaping the screw head and screw point.

4. A method of manufacturing wood screws, comprising the steps of pressing a metal wire of circular cross-section at regular intervals into sections having substantially a rectangular crosssection, pressing a thread into the small sides of each of the sections havinga rectangular crosssection and transforming thereby the sections into pieces having substantially an elliptical crosssection with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, and pressing a thread into the small sides of the elliptical cross-section, thereby reducing the cross-section of the metal sections into a circular cross-section.

5. A method of manufacturing wood. screws comprising the steps of pressing a metal piece of circular cross-section by means of two oppositely arranged flat dies into. a piece having substantially a rectangular cross-section, pressing a thread into the small sides of the rectangular cross-section by means of two oppositely arranged dies located at an angle of with respect to the flat dies and including working faces having sharpened ends and threads and transforming thereby the piece into a piece having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, and pressing a thread into the small sides of the elliptical cross-section by means of two oppositely arranged dies located at an angle of 90 with respect to said last-mentioned two oppositely arranged dies and including working faces having threads, thereby reducing the cross-section of the metal piece into a circular cross-section.

6. A method of manufacturing wood screws comprising the steps of pressing a metal piece of circular cross-section by means of two oppositely arranged flat dies into a piece having substantially a rectangular cross-section, pressing a thread into the small sides of the rectangular cross-section by means of two oppositely arranged dies located at an angle of 90 with respect to the flat dies and including working faces having sharpened ends and threads and transforming thereby the piece into a piece having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, pressing a thread into the small sides of the elliptical cross-section by means of two oppositely arranged dies located at an angle of 90 with respect to said lastmentioned two oppositely arranged dies and including working faces having threads, thereby reducing the cross-section of the metal piece into a circular cross-section, and shaping the screw head and the screw point.

7. A method of manufacturing wood screws comprising the steps of pressing a metal wire of circular cross-section by means of two oppositely arranged fiat dies at regular intervals into sections having substantially a rectangular crosssection, pressing a thread into the small sides of each of the sections having rectangular crosssection by means of two oppositely arranged dies located at an angle of 90 with respect to the flat dies and including working faces having sharpened ends and threads and transforming thereby the pieces into sections having substantially an elliptical cross-section with the major axis of the ellipse arranged parallel to the small side of the rectangular cross-section, and pressing a thread into the small sides of the elliptical crosssection by'means of two oppositely arranged dies located at an angle of 90 to the threaded dies and including working faces having threads, thereby reducing the cross-section of the metal sections into a circularcross-section.

SERAFINO CHIABERTA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 92,567 Belaieff July 13, 1869 478,219 Boyd July 5, 1892 1,466,302 Jouve Aug. 28, 1923 1,535,553 Stambach Apr. 28, 1925 1,680,327 Eicher Aug. 14, 1928 2,129,290 Trurnit Sept. 6, 1938 FOREIGN PATENTS Number Country Date 563,950 France Oct. 10, 1923 

